PV on Green Roofs. Two Years of Comparative Measurement Data from Various System Concepts, Supplemented by Simulation Results and General Considerations

Under Swiss conditions, the optimal use of PV on roof surfaces is just as important as the greening of these surfaces, but the combination of the two involves conflicting objectives. In the project, an energy green roof was realized in which the focus is on the optimal implementation of both approaches. The aim is to show potential customers options for an overall package and to enable a well-founded assessment of the yield. Vertically installed bifacial systems were compared to conventional systems on green roofs. The substructure and substrate structure proved to be easy to install and operate and can be purchased in this form. Substrate thickness and water retention lead to a comparatively strong growth without the need for irrigation, which can nevertheless be easily maintained thanks to the vertical modules. The project can be seen as pioneering with regard to green roofs with high water retention and yet sunny site conditions (vertical PV), which was also demonstrated in the biodiversity studies.